Historically, sail has been used by fishing vessels but this has been superseded by the use of engines over many years. Commercial fishing vessels typically rely on engines to get to and from fishing grounds and to conduct fishing. Use of sail in combination with engines on vessels is typically restricted to leisure sailing vessels rather than commercial fishing vessels. Leisure sail systems are numerous and are often used in combination with engines on leisure vessels. Nevertheless, such systems typically lack the robustness and ease of use required on a commercial fishing vessel.
Adaptations to vessels to allow for fishing, use of engines and/or sail power whilst fishing and use of engines and/or sail power to get to and from fishing grounds can be problematic. Using wind for propulsion, particularly to get to and from fishing grounds, is desirable as it utilises a renewable energy source and reduces the overall carbon emissions from fishing vessels.
For example, sail systems need to be identified that can be broken out reefed and stowed easily and safely. Further, this must be carried out by a crew whose number is dictated by the needs of commercial fishing not by the requirements of rigging the sail(s). In addition, the mast and, if necessary rigging, needs to be mounted and demounted quickly and placed out of the way of the crew when fishing. Indeed, if it is intended to fully integrate the propulsion systems of engine and sail then the goal would be to continue to fish successfully switching from sail power to engine and back again as wind conditions and the working situation dictate.
For example, it may be desirable to have a shorter mast and/or to stow the mast, boom, sail and rigging so as to reduce any leeway their presence introduces to the minimum possible and so provide a more secure working situation when fishing.
It may be desirable to minimise any list introduced by having a sail rig on a commercial fishing vessel arranged so as not to unduly affect the vessel's stability.
It may be desirable for the mast when in a lowered or stowed position to be out of the way of the crew carrying out fishing activities. It may further be desirable for the mast to lie within the periphery of the vessel so as not to extend beyond the periphery of the vessel and thereby get in the way during manoeuvring activities. Further it may be desirable for the mast when upright to be located over a keel of a vessel and/or located over a typical sailing mast location for a vessel (often around ⅓ from the bow of the vessel and ⅔ form aft) and yet be generally centrally or substantially centrally located within the vessel when in a lowered position so as not to unduly affect the centre of gravity and therefore steerability and manoeuvrability of the vessel.
It may also be desirable to minimise the physical space taken up on deck, as this is often limited on fishing vessels. Further it may be desirable not to impact unduly on the provision of a cabin for the crew which is often seen as an essential for fishing in harsh climates.
It may be desirable for the mast when lowered to lie within the length of the vessel e.g. when in port, so as not to obstruct movement of the vessel and reduce the risk of damage to and from other vessels.
Further it may be desirable for the raising or lowering (stepping or un-stepping) of the mast to be effected from within the cabin.
Further it may be desirable if this could be carried out by a single member of crew.
Previously, GB11143 (MCKECHNIE) describes a folding, collapsible, wireless mast having a fixed pivot operated by a hydraulic system.
U.S. Pat. No. 4,655,154 (LEONARD) describes a collapsible mast assembly having a tubular mast support partially open at one side that allows the mast to tilt backwards to a horizontal position. It can then be moved rearwardly or forwardly as desired.
DE102006009206 (HERM SPRENGER) describes a mast laying device with a torsional spring in a hollow mast.
U.S. Pat. No. 4,259,917 (FRANK) describes a foldable mast assembly wherein a main mast is pivotally connected to a stub mast which is pivotally connected to a base secured to the sail boat deck. A removable pin extends between the stub mast and base whereby the main mast and stub mast may be folded to an inoperative position substantially parallel to the main deck and centred approximately lengthwise of the sail boat.
U.S. Pat. No. 6,990,916 (ATWOOD) describes a sail boat mast stepping system in which the mast pivots about a pivot point.
U.S. Pat. No. 4,112,861 (LEWIS) describes a mast stepping and unstepping structure having an upright mast with upper and lower end portions, the lower end pivotally connected to the hull.
DE19835078 (TEPPNER) describes two interlocking spars on a sliding deck mounting.
W095/24334 (LOVELADY) describes a slider assembly for lowering and raising a mast.
W087/00812 (CHRISTENSEN) describes a sail boat having a pivotally mounted mast.
FR2535671 (NAUD) describes a mast on a shaft held by two rigid legs and fixed at one end by a ball and socket joint and at the other to a piece which slides on a rail which makes it possible, in a translational movement of the piece, to lower or raise the mast.
US2008/0035042 (SMITH) describes a system for lifting and lowering a sail boat mast.
U.S. Pat. No. 282,592 (WALTHOUR) describes a device for unshipping masts having a swinging truss.
U.S. Pat. No. 3,827,386 (FADEN) describes a means for lowering the mast on a sail boat in which the lower end of the mast is pivotally and slidably secured to the hull of the sail boat.
Other documents include U.S. Pat. No. 5,243,927 (MESSICK), U.S. Pat. No. 5,865,136 (ALEXANDER), US20020139284 (IACOBONI), U.S. Pat. No. 4,718,370 (PORTEL_VILA), U.S. Pat. No. 4,940,008 (HOYT), U.S. Pat. No. 4,121,530 (ARCE), U.S. Pat. No. 7,418,911 (McCLINTOCK), U.S. Pat. No. 7,137,346 (FRANCKE), U.S. Pat. No. 5,570,651 (SCHIFF), U.S. Pat. No. 7,614,536 (KNISELY), U.S. Pat. No. 4,112,861 (LEWIS), U.S. Pat. No. 4,453,482 (BARKER) and NL9302119.
None of the above documents provide an easily operated mast apparatus suitable for raising and/or lowering a mast and for incorporating into a vessel having an engine and sail.
The above documents describe systems that are over complex to use involving several steps for raising and/or lowering a mast, necessitating the crew moving about the vessel to do so. Further many of the systems described above leave a mast protruding beyond the vessel. Further, the mast when lowered may affect the vessel's centre of gravity and therefore stability and/or manoeuvrability. Some describe outlying rigging that would impede movement of crew on a vessel and necessitate detachment by crew whilst on deck.
Further, in some of the above documents, the mast foot is located in a fixed or fixed but pivotable position on deck.
None of the documents provide a solution suitable for use in a commercial fishing vessel. Further problems remaining include being too flimsy; requiring multi-handed operation; requiring operation from outside the cabin; requiring stabilising lateral stays or lateral supports during use and/or during raising and lowering of the mast; the mast extending outside the vessel when the mast is in a lowered position; de-stabilising the vessel once the mast is lowered because the mast extends over the rear of the vessel; supporting the weight of the mast on a pivot so that it is hard to manoeuvre the mast on the pivot and the pivot is subject to excessive wear and tear; requiring the provision of winch and/or rope pulley or other manual mechanisms for raising and lowering the mast.
The present invention seeks to alleviate one or more of the above problems.